From the March 2009 issue of NOLN.
Quote:
Tech Tips
by Scotti Lee, Ph.D.
NOLN Technical Writer
Canister Filter Media
For much of the past two years, I’ve conducted my own investigation into the media used in many canister filter applications. It’s taken a lot of time and not a little chunk of change, but I’ve found answers to a problem that’s been bugging me since these critters first hit the market a few years back.
Now, we don’t see this problem with all canister filters, and we don’t see it all the time, but it happens often enough to raise my mental red flag.
What happens is that your technician will open up one of these canisters and remove the filter, only to find the filter media is black and even crumbling, usually toward the engine-side of the canister. Whenever this occurs, we immediately note it on the work order and show the customer, then we do our best to clean the inside of the canister, since the crumbling filter has usually left tiny bits of itself everywhere. We wipe the filter housing with shop towels, add a little bit of new oil then use our oil evacuation tool to suck as much of the foreign debris out of the oil system as possible.
The problem is that even these efforts will not be able to remove all the filter media debris. Some of this debris has no doubt worked its way into the tiny oil galleys that riddle a modern automotive engine. This will either slow or stop the flow of oil through these tiny passageways, which may lead to engine damage over the course of time — or sooner depending on how the vehicle is driven.
I’ve sent samples of these damaged filters to labs in Germany and the United States. The results from their tests seem to indicate that there isn’t one single factor that can cause the filter media to break up.
The German labs say they believe the “filter media embrittlement is caused by special aging products in the engine oil entering from the combustion chamber.” Their advice (music to my ears): “Oil drain intervals should be lower.”
Incidentally, they note that in Europe they have not seen this problem because European-spec motor oils tend to veer toward the protection side of the spectrum while our domestic GF-spec motor oils tend to be formulated for fuel economy. This should tell us something about the development of the GF-series of motor oil.
The two labs I used domestically offered a different explanation. The filter media — its technical name is phenolic media — is not just heavy folded paper. It’s been treated with different chemicals to give it properties that will make for good filtration, pleating, tensile strength, tear stiffness and color. The U.S. labs found an unusually high nitrogen content in the damaged media, which they hypothesized was the result of the media being subjected to “heat for a long period of time,” or being subjected to “very high heat” for a shorter period of time.
I have a few thoughts on canister air filters. First, many of these applications are located in areas that receive little air circulation or are near the exhaust manifold. In both instances, the media inside the filter will either receive little circulatory cooling or will be near a source of extreme heat.
Second, with automakers pushing longer oil change intervals, it’s natural for drivers to take the OEM recommendation and stretch it out a bit. This stretching could be damaging the filter media in some instances. Further, extended intervals mean drivers are having their oil levels checked less often (because how many drivers do you see at the gas station checking their own oil). I don’t know about you, but at our shop most of the vehicles are coming in with oil levels that are a tad low. This means dirtier oil and a hotter-running engine — and more problems for the filter media.
Finally, if the GF-series of motor oil specifications is really contributing to this problem, what will happen when GF-5 is introduced in the middle of next year? Questions like that keep me up at night.
Scotti Lee is operator of Oil Change Express in New Castle, Delaware. He may be reached at 302-324-1900.
Quote:
Tech Tips
by Scotti Lee, Ph.D.
NOLN Technical Writer
Canister Filter Media
For much of the past two years, I’ve conducted my own investigation into the media used in many canister filter applications. It’s taken a lot of time and not a little chunk of change, but I’ve found answers to a problem that’s been bugging me since these critters first hit the market a few years back.
Now, we don’t see this problem with all canister filters, and we don’t see it all the time, but it happens often enough to raise my mental red flag.
What happens is that your technician will open up one of these canisters and remove the filter, only to find the filter media is black and even crumbling, usually toward the engine-side of the canister. Whenever this occurs, we immediately note it on the work order and show the customer, then we do our best to clean the inside of the canister, since the crumbling filter has usually left tiny bits of itself everywhere. We wipe the filter housing with shop towels, add a little bit of new oil then use our oil evacuation tool to suck as much of the foreign debris out of the oil system as possible.
The problem is that even these efforts will not be able to remove all the filter media debris. Some of this debris has no doubt worked its way into the tiny oil galleys that riddle a modern automotive engine. This will either slow or stop the flow of oil through these tiny passageways, which may lead to engine damage over the course of time — or sooner depending on how the vehicle is driven.
I’ve sent samples of these damaged filters to labs in Germany and the United States. The results from their tests seem to indicate that there isn’t one single factor that can cause the filter media to break up.
The German labs say they believe the “filter media embrittlement is caused by special aging products in the engine oil entering from the combustion chamber.” Their advice (music to my ears): “Oil drain intervals should be lower.”
Incidentally, they note that in Europe they have not seen this problem because European-spec motor oils tend to veer toward the protection side of the spectrum while our domestic GF-spec motor oils tend to be formulated for fuel economy. This should tell us something about the development of the GF-series of motor oil.
The two labs I used domestically offered a different explanation. The filter media — its technical name is phenolic media — is not just heavy folded paper. It’s been treated with different chemicals to give it properties that will make for good filtration, pleating, tensile strength, tear stiffness and color. The U.S. labs found an unusually high nitrogen content in the damaged media, which they hypothesized was the result of the media being subjected to “heat for a long period of time,” or being subjected to “very high heat” for a shorter period of time.
I have a few thoughts on canister air filters. First, many of these applications are located in areas that receive little air circulation or are near the exhaust manifold. In both instances, the media inside the filter will either receive little circulatory cooling or will be near a source of extreme heat.
Second, with automakers pushing longer oil change intervals, it’s natural for drivers to take the OEM recommendation and stretch it out a bit. This stretching could be damaging the filter media in some instances. Further, extended intervals mean drivers are having their oil levels checked less often (because how many drivers do you see at the gas station checking their own oil). I don’t know about you, but at our shop most of the vehicles are coming in with oil levels that are a tad low. This means dirtier oil and a hotter-running engine — and more problems for the filter media.
Finally, if the GF-series of motor oil specifications is really contributing to this problem, what will happen when GF-5 is introduced in the middle of next year? Questions like that keep me up at night.
Scotti Lee is operator of Oil Change Express in New Castle, Delaware. He may be reached at 302-324-1900.
